Migratory patterns and habitat use of the sand tiger shark (Carcharias taurus) in the western North Atlantic

2015 ◽  
Vol 66 (2) ◽  
pp. 158 ◽  
Author(s):  
Shara M. Teter ◽  
Bradley M. Wetherbee ◽  
Dewayne A. Fox ◽  
Chi H. Lam ◽  
Dale A. Kiefer ◽  
...  
Keyword(s):  
Habitat Use ◽  
North Atlantic ◽  
Delaware Bay ◽  
Tiger Shark ◽  
Population Declines ◽  
Vertical Movements ◽  
Migratory Patterns ◽  
By Catch ◽  
Tiger Population ◽  
Carcharias Taurus

Globally, population declines for the sand tiger shark (Carcharias taurus) have resulted in calls for informed management of populations, including in the western North Atlantic, where they have been listed as a Species of Concern by NOAA Fisheries. However, information on movements and habitat use, critical for informed management of this sand tiger population, is limited. We investigated horizontal and vertical movements of sand tigers along the US east coast using pop-up archival satellite transmitters, supplemented by acoustic telemetry. Thirteen sand tiger sharks were tagged with satellite and acoustic transmitters in Delaware Bay in late August and early September 2008. Ten of these provided satellite data for horizontal tracks using a Kalman filter. Males left Delaware Bay in autumn and moved south along the continental shelf until reaching waters off North Carolina. Females moved east to waters near the edge of the continental slope. Average depth of males was positively correlated with shark size. All individuals spent at least 95% of their time in waters of 17–23°C. Sand tiger sharks appear most susceptible to fisheries in November and December. Slight expansion of the boundaries and timing of an existing shark-directed bottom longline area closure would likely reduce by-catch of sand tiger sharks and enhance recovery of the stock.

Maximum age and missing time in the vertebrae of sand tiger shark (Carcharias taurus): validated lifespan from bomb radiocarbon dating in the western North Atlantic and southwestern Indian Oceans

2014 ◽  
Vol 65 (8) ◽  
pp. 674 ◽  
Author(s):  
M. S. Passerotti ◽  
A. H. Andrews ◽  
J. K. Carlson ◽  
S. P. Wintner ◽  
K. J. Goldman ◽  
...  
Keyword(s):  
North Atlantic ◽  
Tiger Shark ◽  
Carbon 14 ◽  
Growth Bands ◽  
Bomb Radiocarbon ◽  
Future Work ◽  
Large Adult ◽  
Vertebral Growth ◽  
Age Estimates ◽  
Carcharias Taurus

Bomb radiocarbon analysis of vertebral growth bands was used to validate lifespan for sand tiger sharks (Carcharias taurus) from the western North Atlantic (WNA) and southwestern Indian Oceans (SIO). Visual counts of vertebral growth bands were used to assign age and estimate year of formation (YOF) for sampled growth bands in eight sharks from the WNA and two sharks from the SIO. Carbon-14 results were plotted relative to YOF for comparison with regional Δ14C reference chronologies to assess the accuracy of age estimates. Results from the WNA validated vertebral age estimates up to 12 years, but indicated that ages of large adult sharks were underestimated by 11–12 years. Age was also underestimated for adult sharks from the SIO by 14–18 years. Validated lifespan for C. taurus individuals in the present study reached at least 40 years for females and 34 years for males. Findings indicated that the current age-reading methodology is not suitable for estimating the age of C. taurus beyond ~12 years. Future work should investigate whether vertebrae of C. taurus record age throughout ontogeny, or cease to be a reliable indicator at some point in time.

scholarly journals Habitat use patterns of franciscana dolphins (Pontoporia blainvillei) off southern Brazil in relation to water depth

2009 ◽  
Vol 89 (5) ◽  
pp. 943-949 ◽  
Author(s):  
Daniel Danilewicz ◽  
Eduardo R. Secchi ◽  
Paulo H. Ott ◽  
Ignacio B. Moreno ◽  
Manuela Bassoi ◽  
...  
Keyword(s):  
Habitat Use ◽  
Rio Grande ◽  
Limiting Factors ◽  
Small Scale ◽  
Southern Brazil ◽  
Rio Grande Do Sul ◽  
Use Patterns ◽  
Management Procedures ◽  
By Catch ◽  
Pontoporia Blainvillei

The patterns of habitat use by the franciscana dolphins (Pontoporia blainvillei) along its distribution are poorly known. This study investigates the patterns of habitat use with respect to depth for 181 individuals of different age, size, gender and reproductive condition off Rio Grande do Sul, southern Brazil. The results reveal that franciscanas are very homogeneously distributed according to depth. Individuals from all lengths utilize nearly the entire range of depths of the surveyed area. Larger or older animals do not use deeper waters than younger animals, indicating that body size and age are not limiting factors for franciscanas that occupy deeper or offshore waters. Gestation seems to not cause a change in the distribution of females. Although the sex-ratio of the overall data did not vary from 1:1 in different depth intervals, a small-scale comparison between the northern and southern coast demonstrated the existence of some kind of sexual segregation. Franciscana by-catch in Rio Grande do Sul is not sustainable and it is agreed that management procedures are needed. Nevertheless, the available data on species distribution do not allow the designing of a protected area in order to minimize the by-catches of a particular sex/reproductive class.

Tiger shark (Galeocerdo cuvier) movement patterns and habitat use determined by satellite tagging in eastern Australian waters

2014 ◽  
Vol 161 (11) ◽  
pp. 2645-2658 ◽  
Author(s):  
Bonnie J. Holmes ◽  
Julian G. Pepperell ◽  
Shane P. Griffiths ◽  
Fabrice R. A. Jaine ◽  
Ian R. Tibbetts ◽  
...  
Keyword(s):  
Habitat Use ◽  
Movement Patterns ◽  
Tiger Shark ◽  
Galeocerdo Cuvier ◽  
Satellite Tagging

scholarly journals A globally threatened shark, Carcharias taurus, shows no population decline in South Africa

2020 ◽  
Vol 10 (1) ◽  
Author(s):  
Juliana D. Klein ◽  
Aletta E. Bester-van der Merwe ◽  
Matthew L. Dicken ◽  
Arsalan Emami-Khoyi ◽  
Kolobe L. Mmonwa ◽  
...  
Keyword(s):  
South Africa ◽  
Census Data ◽  
Demographic History ◽  
Conservation Status ◽  
Population Decline ◽  
Multilocus Genotype ◽  
Population Declines ◽  
Effective Population ◽  
Anthropogenic Pressures ◽  
Carcharias Taurus

Abstract Knowledge about the demographic histories of natural populations helps to evaluate their conservation status, and potential impacts of natural and anthropogenic pressures. In particular, estimates of effective population size obtained through molecular data can provide useful information to guide management decisions for vulnerable populations. The spotted ragged-tooth shark, Carcharias taurus (also known as the sandtiger or grey nurse shark), is widely distributed in warm-temperate and subtropical waters, but has suffered severe population declines across much of its range as a result of overexploitation. Here, we used multilocus genotype data to investigate the demographic history of the South African C. taurus population. Using approximate Bayesian computation and likelihood-based importance sampling, we found that the population underwent a historical range expansion that may have been linked to climatic changes during the late Pleistocene. There was no evidence for a recent anthropogenic decline. Together with census data suggesting a stable population, these results support the idea that fishing pressure and other threats have so far not been detrimental to the local C. taurus population. The results reported here indicate that South Africa could possibly harbour the last remaining, relatively pristine population of this widespread but vulnerable top predator.

Migration patterns and seasonal forest use by birds in the Brazilian Pantanal

2017 ◽  
Vol 27 (3) ◽  
pp. 371-387 ◽  
Author(s):  
JOÃO BATISTA DE PINHO ◽  
MÔNICA ARAGONA ◽  
KARLO YOSHIHIRO PIOTO HAKAMADA ◽  
MIGUEL ÂNGELO MARINI
Keyword(s):  
Habitat Use ◽  
Bird Species ◽  
Occupancy Models ◽  
Neotropical Forests ◽  
Migration Patterns ◽  
Point Counts ◽  
Run Off ◽  
Forest Use ◽  
Migratory Patterns ◽  
Landscape Units

SummaryThe use of forest habitats and migratory patterns are still unclear for tropical birds. Some are described herein for the Pantanal wetlands of Brazil. Thus, our aim was to describe different patterns of forest habitat use by birds and classify the birds’ migration patterns for the northern Pantanal region, Brazil. From September 1999 to December 2003, we sampled four forest types, during which we collected standardised data with mist-net captures and point counts, with additional ad lib. observations. We recorded 214 bird species: 113 (52.8%) were total habitat generalists; 41 (19.2%) were forest generalists; 19 (8.9%) were flooded habitat specialists; and 28 (13.1%) were not classified due to the low number of records; three other categories of habitat use divide the remaining 6% of records. About half of the species showed some migratory behaviour, these were classified by us according to the season they spent in the area: 121 species (56.5%) as residents, 28 (13.1%) as run-off and dry migrants, 11 (5.1%) as run-off (winter) migrants, eight (3.7%) as dry (breeding) migrants, eight (3.7%) as dry and flooding (summer) migrants, eight (3.7%) as flooding migrants, three (1.4%) as flooding and run-off migrants, and 27 (12.6%) as uncommon. We constructed community occupancy models with six of the eight patterns of migration described; flooding migrants and run-off migrants were not modelled since the few species recorded also had very few detections. As expected, the model confirmed that species from all six tested migration patterns arrive and depart from the Pantanal across the seasons. Contrary to most Neotropical forests, there was a high percentage (43.5%) of non-resident species. The results show the need of investing heavily in preserving different landscape units within the Pantanal, but also in the surrounding Cerrado region, in order to conserve resident and short distance intra-tropical migrants.

Coeliotomy under general anaesthesia and removal of an enterolith from a sand tiger shark ( Carcharias taurus )

2016 ◽  
Vol 4 (2) ◽  
Author(s):  
Tania Monreal‐Pawlowsky ◽  
Susan M Thornton ◽  
Mark Frederick Stidworthy ◽  
Paul Hale
Keyword(s):  
General Anaesthesia ◽  
Tiger Shark ◽  
Carcharias Taurus

Using bomb radiocarbon analyses to validate age and growth estimates for the tiger shark, Galeocerdo cuvier, in the western North Atlantic

2008 ◽  
Vol 154 (3) ◽  
pp. 423-434 ◽  
Author(s):  
Jeff Kneebone ◽  
Lisa J. Natanson ◽  
Allen H. Andrews ◽  
W. Hunt Howell
Keyword(s):  
North Atlantic ◽  
Age And Growth ◽  
Tiger Shark ◽  
Galeocerdo Cuvier ◽  
Bomb Radiocarbon

Retrospective examination of habitat use by blueback herring (Alosa aestivalis) using otolith microchemical methods

2015 ◽  
Vol 72 (7) ◽  
pp. 1073-1086 ◽  
Author(s):  
Molly L. Payne Wynne ◽  
Karen A. Wilson ◽  
Karin E. Limburg
Keyword(s):  
Habitat Use ◽  
Life Histories ◽  
First Year ◽  
Low Salinity ◽  
Blueback Herring ◽  
Alosa Aestivalis ◽  
Sr:Ca Ratios ◽  
Migratory Patterns ◽  
Retrospective Examination ◽  
Diadromous Species

Understanding the location and duration of habitat use by young fish is important for management and restoration efforts, but is largely unknown in anadromous species. We used otolith microchemistry and ambient water concentrations of Ca, Ba, Mn, and Sr to identify habitat use in the first year of growth for 131 returning adult blueback herring (Alosa aestivalis) collected in seven spawning runs along the coast of Maine, USA. Ambient Sr:Ca ratios were correlated with salinity and were used as primary indicators of habitat use. Results revealed variable individual migration histories with several discrete migratory patterns; some fish migrated into seawater well before the end of the first year, while the majority exhibited longer residency in freshwater or low salinity habitat. Total area of available habitats ranged from approximately 213 to 6053 ha fresh water and 204 to 3395 ha estuary. Residency in freshwater or low salinity habitats was positively correlated with extent of freshwater habitat (r = 0.37, P < 0.001). Results emphasize the importance of conserving a variety of habitat types to maintain variation in life histories and ensure plasticity in migratory behavior of diadromous species.

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